This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. In this project we will develop an ultra high-speed parallel MRSI technique for the human breast based on Proton Echo Planar Spectroscopic Imaging (PEPSI) and parallel MRI (SENSE/GRAPPA). We will assess the feasibility of single-shot PEPSI with Superresolution SENSE reconstruction (SURE-SENSE), a novel form of parallel MRI, which is particularly suitable for low resolution MRSI. This methodology will be implemented using a novel 16-channel breast RF array coil that provides significantly higher sensitivity and enables much faster parallel imaging acceleration as compared to conventional RF coil designs. Our preliminary results in the human breast demonstrate the feasibility of high quality 2D and 3D PEPSI in short measurement time. Our aims are to 1) Develop ultra high-speed parallel 3D MRSI for the breast at 3 T;and 2) Use ultra high-speed 3D MRSI at 3 T as a tool for breast cancer detection and treatment response assessment. If successful, the developed technique will be used as a tool for breast cancer diagnosis and treatment monitoring. The long-term goals are to utilize MRSI as an early predictor of treatment failure in women undergoing systemic therapy (i.e. chemotherapy, endocrine therapy) for breast cancer and to develop an improved screening protocol for high-risk patients. In patients undergoing neoadjuvant therapies, accurate early identification of treatment failure or success could save significant time and resources, and minimize patient risk and exposure to potential side effects from medications that are not efficacious.